Groups | Search | Server Info | Login | Register

Groups > sci.electronics.design > #743737

Re: TCLE

Show all headers | View raw

Am 05.05.26 um 20:15 schrieb someone:
> And there's only one receiver, right? Otherwise you'll be applying half 
> signal level to some of them until the reflection works it way back, 
> resulting in possible metastability. Source terminated works best with 
> very fast signal edge rates. Does that Tiny Logic drive those low 
> impedances, somewhere in the 100- 300 ohm range, to full VinH,min and 
> VinL,max, or is the receiver not a logic gate?
> 
> That so-called elegant solution with the '245 reminds me of the days of 
> MSI logic CPUs with all sorts of multi-phase clock references all over 
> the place, anything of any complexity consumed kilowatts, and the 
> cooling exhaust air was coming out hot enough to burn your hands. The 5V 
> was routed on true bus bars about 1/2 inch thick.
> 
> All they did with the 74245 was tap off the conventional TTL phase 
> splitter used to drive a single totempole output, and use it to drive 
> two totempoles, true and complementary. The phase splitter outputs 
> totempole drives were mirror images and in that way achieved theoretical 
> zero skew. Looks like they were after eliminating transmission line 
> common mode reflection with that skew performance, so the market went 
> away with the necessity to drive clock signals tens of feet in distance.


This circuit: 2*74LVC04 + 2*100R ser running at 5V
(well inside Vabs max)

< 
https://www.flickr.com/photos/137684711@N07/32245910240/in/datetaken/lightbox/ 
  >

delivers that into a scope, switched to Zin = 50 Ohm:

click to > once or twice.

Sorry for the colors, they look better on the screen than in the screen 
dump.
I'd say: Good enough for 3V3 74LVC input with 50R parallel termination.

Without the series resistors, it's probably OK for 5V CMOS. Just keep
the micro strip at 50 Ohm then.

Gerhard

Back to sci.electronics.design | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

TCLE john larkin <jl@glen--canyon.com> - 2026-05-03 07:09 -0700
  Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-04 01:19 +1000
    Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-03 10:05 -0700
      Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-04 17:06 +1000
        Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-04 04:19 -0700
          Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-05 03:13 +1000
            Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-04 12:08 -0700
              Re: TCLE Jan Panteltje <alien@comet.invalid> - 2026-05-05 06:54 +0000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-05 07:34 -0700
                Re: TCLE Jan Panteltje <alien@comet.invalid> - 2026-05-05 16:57 +0000
              Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-05 17:29 +1000
                Re: TCLE Jeroen Belleman <jeroen@nospam.please> - 2026-05-05 12:40 +0200
                Re: TCLE "Edward Rawde" <invalid@invalid.invalid> - 2026-05-05 09:58 -0400
                Re: TCLE "Edward Rawde" <invalid@invalid.invalid> - 2026-05-05 10:09 -0400
                Re: TCLE "Edward Rawde" <invalid@invalid.invalid> - 2026-05-05 10:10 -0400
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-06 02:30 +1000
                Re: TCLE "Edward Rawde" <invalid@invalid.invalid> - 2026-05-05 12:46 -0400
                Re: TCLE piglet <erichpwagner@hotmail.com> - 2026-05-05 19:44 +0100
                Re: TCLE "Edward Rawde" <invalid@invalid.invalid> - 2026-05-05 15:30 -0400
                Re: TCLE Jeroen Belleman <jeroen@nospam.please> - 2026-05-05 18:37 +0200
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-06 02:15 +1000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-05 07:41 -0700
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-06 02:38 +1000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-05 11:52 -0700
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-08 04:25 +1000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-07 13:14 -0700
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-08 15:03 +1000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-08 03:26 -0700
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-08 22:26 +1000
  Re: TCLE Lasse Langwadt <llc@fonz.dk> - 2026-05-03 19:12 +0200
    Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-03 12:01 -0700
      Re: TCLE Lasse Langwadt <llc@fonz.dk> - 2026-05-04 23:30 +0200
        Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-04 15:06 -0700
          Re: TCLE Lasse Langwadt <llc@fonz.dk> - 2026-05-05 00:50 +0200
            Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-04 15:58 -0700
              Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-05 17:36 +1000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-05 11:48 -0700
                Re: TCLE Bill Sloman <bill.sloman@ieee.org> - 2026-05-06 18:45 +1000
                Re: TCLE Lasse Langwadt <llc@fonz.dk> - 2026-05-05 22:55 +0200
              Re: TCLE someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-05-05 18:15 +0000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-05 11:38 -0700
                Re: TCLE Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-05-05 19:25 +0000
                Re: TCLE john larkin <jl@glen--canyon.com> - 2026-05-05 13:41 -0700
                Re: TCLE Lasse Langwadt <llc@fonz.dk> - 2026-05-06 00:05 +0200
                Re: TCLE Gerhard Hoffmann <dk4xp@arcor.de> - 2026-05-05 21:09 +0200
  Re: TCLE "Edward Rawde" <invalid@invalid.invalid> - 2026-05-03 15:49 -0400

csiph-web